In a data storage system, a plurality of copies of data may be stored simultaneously so as to enhance security and availability of the data. For example, data may be replicated from one storage device to another storage device through a mirror view technology. Currently, data replication may be performed through synchronous replication or asynchronous replication.
Synchronous replication refers to a technology of generating, by a network attached storage (NAS), a plurality of synchronous data copies in a local area network (LAN) or Wide area network (WAN) via block replication technique. An advantage of synchronous replication is small time delay of data synchronous protection and a 0 recovery point objective (RPO). Therefore, a disaster event occurring at a production data center may not result in data loss; however, it can only work within a relative short distance (e.g., 10 KM). Therefore, synchronous replication is suitable for applications with a low recovery time objective (RTO).
Compared with synchronous replication, with the technique of asynchronous replication, there is a longer time delay before data is replicated to a secondary site. The asynchronous replication can support a longer distance. e.g., 100 KM.
Therefore, the synchronous replication and asynchronous replication have their own advantages and disadvantages and are applicable to different scenarios. In current storage systems, there have been no technical solutions to support co-existence of synchronous replication and asynchronous replication.